JP2009104439A - Servo actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a servo actuator enabling anyone to easily perform gain adjustment thereof. <P>SOLUTION: The servo actuator has a speed feedback loop for controlling the speed of a motor, inserts a notch filter means into the speed feedback loop, and eliminates mechanical resonance, and the actuator includes: a data collection means for acquiring data showing a frequency response characteristic of the speed feedback loop; a moving average means for performing moving average processing of the data acquired by the data collection means; a comparison means for comparing data obtained by the moving average means with data obtained by the data collection means to extract a resonance characteristic of the speed feedback loop; and a notch filter setting means for setting a frequency and Q value of the notch filter means on the basis of the resonance characteristic extracted by the comparison means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a servo actuator having notch filter means inserted in the middle of a speed feedback loop for controlling the speed of a motor.

  Patent Document 1 discloses a technical disclosure of a servo actuator in which notch filter means is inserted in the middle of a speed feedback loop in order to eliminate mechanical resonance generated in a motor.

  FIG. 5 is a functional block diagram showing a configuration example of a position control apparatus for a workpiece 2 using a servo actuator having a conventional configuration. The position of the workpiece whose movement is controlled by the motor 1 is detected by the position detection means 3. A speed detection value Vf is generated by the speed generation means 4 from the difference of the position detection value Pf.

  A deviation between the position command Pi and the position detection value Pf is calculated by the position control means 5 and a speed command Vi is output. The deviation between the speed command Vi and the detected speed value Vf is calculated by the speed control means 6 and a current command F is output. The current command value F is input to the driver 8 through the notch filter means 7.

  The driver 8 outputs a current I to the motor 1 based on the current command F, and moves the workpiece 2. The frequency response characteristic of the speed feedback loop including the motor 1 can be measured off-line by the response of the speed detection value Vf to the simulation signal Sf from the simulation means 9 and can be output to the file 10.

  FIG. 6 is a frequency response characteristic diagram of the speed feedback loop. The loop gain decreases as the frequency increases, but there are pulse-like peaks P1, P2, P3, and P4 due to mechanical resonance of the system including the motor. Normally, the loop gain cannot be increased in order to suppress mechanical resonance.

  As a countermeasure, resonance is suppressed by inserting notch filter means 7 matched with the resonance frequency of the mechanical resonance into the speed control loop. By using the notch filter means 7, speeding up of the position control is realized. The notch filter means 7 is set by adjusting the applied frequency f and Q value.

  The operator 11 checks the frequency response characteristics of the file 10 to read the resonance characteristics, and determines and manually sets the frequency f and Q value applied to the notch filter means 7 based on experience.

JP-A-5-19858

  In the conventional setting method, the notch filter means 7 is manually set by a person reading the resonance characteristic from the frequency response characteristic. Therefore, the setting of the appropriate notch filter means depends on the individual experience.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to realize a servo actuator that anyone can easily perform gain adjustment.

In order to achieve such a subject, the present invention has the following configuration.
(1) In a servo actuator having a speed feedback loop for controlling the speed of a motor and inserting notch filter means into the speed feedback loop to remove mechanical resonance,
Data collection means for obtaining data indicating frequency response characteristics of the speed feedback loop;
Moving average means for moving average processing the data acquired by the data collection means;
Comparison means for comparing the data obtained by the moving average means with the data obtained by the data collection means to extract the resonance characteristic of the speed feedback loop;
Notch filter setting means for setting the frequency and Q value of the notch filter means based on the resonance characteristics extracted by the comparison means;
A servo actuator comprising:

(2) Based on the output of the comparison means, a portion where the waveform on which the moving average processing has been executed exceeds a specific threshold value as compared with the waveform before the execution is collected as peak data, and the peak data having a maximum maximum value is collected as the notch filter The servo actuator according to (1), further comprising: a peak data collection unit that outputs the set frequency to the notch filter setting unit.

(3) an intersection detection means for obtaining an intersection with the waveform obtained by performing the moving average process on the peak data having a large maximum value;
Q value calculating means for calculating a Q value such that a predetermined gain falls at the obtained intersection and outputting it to the notch filter setting means;
The servo actuator according to (1) or (2), comprising:

(4) It is provided with simulation means for inputting simulated data to the speed feedback loop, acquiring the speed feedback data, and outputting the data to the data collecting means as data indicating the frequency response characteristics of the motor (1) The servo actuator according to any one of (3) to (3).

According to the configuration of the present invention, the following effects can be expected.
According to the present invention, since the adjustment of the notch filter means of the servo actuator can be automated, an operator having experience is not required, and a servo actuator that allows anyone to easily perform gain adjustment can be realized.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a functional block diagram showing an embodiment of a position control device using a servo actuator to which the present invention is applied. The same elements as those of the conventional apparatus described with reference to FIG.

  The structural feature of the present invention is that a notch filter automatic setting unit 100 is provided in place of the operator 11 of the conventional apparatus. The functional configuration of the notch filter automatic setting unit 100 includes a data collection unit 101, a moving average unit 102, a comparison unit 103, a peak data collection unit 104, an intersection detection unit 105, a Q value calculation unit 106, and a notch filter setting unit 107.

  The simulation means 9 inputs the simulation signal Sf to the speed feedback loop offline and acquires the speed feedback data. Then, the obtained data is output to the data collecting means 101 as data indicating the frequency response characteristics of the motor.

  The moving average unit 102 performs a moving average process on the acquired frequency response characteristic data and passes it to the comparison unit 103. The comparison unit 103 compares the waveform before the moving average process with the waveform after the execution of the movement process, and passes the comparison data to the peak data collection unit 104.

  FIG. 2 is a characteristic diagram showing the relationship between the waveform of the frequency response characteristic and the waveform after moving average processing. The peak data collection means 104 has a portion of the waveform in which the waveform before the moving average process protrudes above the predetermined threshold E more than the waveform after the moving average process on the higher frequency side than the zero cross frequency fz of the frequency response characteristic. P1 to P4 are collected as notable peaks.

  The peak data collection unit 104 pays attention to the resonance characteristic to be applied to the notch filter as the peak value among the collected peak data, and passes it to the notch filter setting unit 107 and the intersection detection unit 105 as frequency setting information.

  FIG. 3 is a characteristic diagram showing the relationship between the peak data, the moving average level, and the threshold value. The intersection detection unit 105 obtains intersection frequencies f1 and f2 with the level AV on which the moving average process created by the moving average unit 102 is performed on the peak data of interest, and passes this data to the Q value calculation unit 106.

  Based on the intersections f1 and f2 obtained by the intersection detection unit 105, the Q value calculation unit 106 calculates a Q value such that the gain drops by a specific numerical value, and passes it to the notch filter setting unit 107 as Q value setting information.

  The notch filter setting means 107 acquires the frequency setting information from the peak data collection means 104 and the Q value setting information from the Q value calculation means 106 and automatically sets the frequency f and Q value applied to the notch filter means 7.

  In the embodiment of FIG. 1, the case where the frequency and Q value of the notch filter unit 7 are set for one peak data focused on by the peak data collection unit 104 has been described. However, it is necessary to suppress a plurality of resonance characteristics. In some cases, the notch filter means 7 is inserted in series in a plurality of stages, the intersection detection means 105 and the Q value calculation means are configured to correspond to the plurality of peak data corresponding to the plurality of peak data of interest, and the notch filter What is necessary is just to take the structure which sets a frequency and Q value to each means.

  FIG. 4 is a frequency response characteristic diagram of a speed feedback loop to which the present invention is applied. In this example, P1 and P2 are selected as notable peaks, the frequency and Q value of the notch filter means 7 are set for these two points, and the resonance characteristics are suppressed.

  In the present invention, since the frequency response characteristic of the speed feedback loop is acquired offline, the resonance frequency can be grasped in advance prior to the operation of the servo actuator. Therefore, the possibility of an accident can be reduced as compared with the setting of the notch filter means in the online state. Further, the result when a specific frequency and Q value are set in the notch filter means can be confirmed in advance.

  In the above-described embodiment, the application target of the present invention has been described as a servo actuator including a motor. However, the present invention is generally used when a resonance characteristic is suppressed by a notch filter unit in a mechanical system having a resonance characteristic. It is possible.

It is a functional block diagram showing one embodiment of a position control device using a servo actuator to which the present invention is applied. It is a characteristic view which shows the relationship between the waveform of a frequency response characteristic, and the waveform after a moving average process. It is a characteristic view which shows the relationship between peak data, a moving average level, and a threshold value. It is a frequency response characteristic figure of the speed feedback loop to which the present invention is applied. It is a functional block diagram which shows the structural example of the position control apparatus using the servo actuator of a conventional structure. It is a frequency response characteristic figure of a speed feedback loop.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2 Workpiece | work 3 Position detection means 4 Speed generation means 5 Position control means 6 Speed control means 7 Notch filter means 8 Driver 9 Simulation means 100 Notch filter automatic setting part 101 Data collection means 102 Moving average means 103 Comparison means 104 Peak data collection Means 105 Intersection detection means 106 Q-value calculation means 107 Notch filter setting means

Claims (4)

In a servo actuator having a speed feedback loop for controlling the speed of the motor, and inserting notch filter means in this speed feedback loop to eliminate mechanical resonance,
Data collection means for obtaining data indicating frequency response characteristics of the speed feedback loop;
Moving average means for moving average processing the data acquired by the data collection means;
Comparison means for comparing the data obtained by the moving average means with the data obtained by the data collection means to extract the resonance characteristic of the speed feedback loop;
Notch filter setting means for setting the frequency and Q value of the notch filter means based on the resonance characteristics extracted by the comparison means;
A servo actuator comprising:   Based on the output of the comparison means, a portion where the waveform that has been subjected to the moving average processing exceeds a specific threshold value than the waveform before the execution is collected as peak data, and the peak data having a large maximum value is set to the set frequency of the notch filter means. The servo actuator according to claim 1, further comprising: a peak data collecting unit that outputs to the notch filter setting unit. An intersection detection means for obtaining an intersection with the waveform obtained by performing the moving average processing on the peak data having a large maximum value;
Q value calculating means for calculating a Q value such that a predetermined gain falls at the obtained intersection and outputting it to the notch filter setting means;
The servo actuator according to claim 1, further comprising:   4. Simulation means for inputting simulated data to the speed feedback loop, acquiring the speed feedback data, and outputting it to the data collecting means as data indicating a frequency response characteristic of the motor. The servo actuator according to any one of the above.

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